1. Field of the Invention
The invention relates to a method to make parts, made of continuous fiber and resin based composite materials, having stamped shapes, as well as to a device for the implementing of this method.
2. Description of the Prior Art
Increasingly today, parts are being made of composite materials based on a synthetic resin binder that takes continuous fibers. The resin is either a thermoplastic or thermo-hardening resin, for example, epoxide or polystyrilpyridine or again, polyimide, and the fibers are glass fibers, carbon fibers or else a mixture of fibers of various materials.
There are many methods currently used to make composite material parts with special embossed features.
For example, there is the known air-slip technique in which a knotted-fiber based fabric, preimpregnated with resin, is used to obtain a part with special embossments by making folds in the fabric and polymerizing the resin when the desired shape is obtained. This technique gives parts with precise mechanical characteristics, but the making of the folds during the air-slip process creates finishing problems and requires the part to be stamped or put in a high pressure autoclave, and this entails heavy investment.
Another method consists in the stamping of an oriented superimposition of single-directional layers of resin-impregnated fibers followed by a polymerizing operation. A method of this type is described, in particular, in the U.S. Pat. No. 2,115,065. This method has a certain number of disadvantages. Thus, during the stamping operation, the fibers may be shifted in a disordered way, and this will affect the rigidity of the part. Finally, the use of preimpregnated fabric causes major stresses in the fibers during the stamping process, and this may cause them to break.
An object of the invention is a method which can be used to make parts out of composite materials based on continuous fibers and a binder, said parts having stamped shapes and fibers which are not damaged during manufacture.